The present invention refers to a an adjustable dispenser for granular substances, such as seeds, fertilizers and the like, to be used for agricultural purposes.
Dispensers of the above cited kind have been known for a long time now and, in particular, they are used to evenly distribute the substances along several different rows. These dispensers are of either a mechanical or a pneumatic kind, depending on the type of operation thereof.
Mechanical dispensers are generally formed by a container, into which the granules of the substance to be dispensed are filled, and a motor-driven rotator, which feeds said granules through a plurality of outlets so as to let them fall on the ground.
The main problem encountered with these dispensers is due to the requirement that they provide as high an extent as possible of evenness in the distribution of the substances being dispensed, regardless of their being seeds, granular fertilizers or the like, in order to allow for a regular growth of the crops, i.e. the agricultural products being cultivated. Similarly important is the problem connected with the fact that these dispensers should possibly be designed as multi-functional units, i.e. units that are capable of being adapted to dispense differently shaped and sized seeds and granular substances.
The patent publication DE 932 040 describes a dispenser in which, within the container, there is a rotatable, a cone-shaped, vertical-axis rotator which cooperates with a wheel that is rotatable about a horizontal axis so as to unload a single seed at a time onto the ground. A similar solution is described in the patent publication GB 417,942, in which the wheel for sorting and unloading the seeds is replaced by the lower rim of the rotator, which is provided with recesses, or impressions, adapted to accommodate individual seeds. An arrangement is disclosed in this patent, which is provided with two dispensers that are operated by a single driving shaft through appropriate motion transmission mechanisms of the bevel gear pair type.
The patent publication U.S. Pat. No. 3,347,426 describes a precision seeder, in which the seeds are sorted with the help of a cylindrical rotator provided with a cladding of soft material and adapted to rotate about a horizontal axis. Finally, the patent publication EP 0 769 896 differs from the above cited one in that the rotator, still having a cylindrical shape and a cladding of soft material, is adapted to rotate about a vertical axis and cooperates with a disc-shaped peripheral guide, on the inner surface of which there are provided recesses, or impressions, for sorting and unloading the seeds.
All of the above-discussed prior-art dispensers share the drawback of necessarily requiring the rotator to be replaced when changing over to the distribution of a different product, i.e. a product having a different size or shape with respect to the previously dispensed substance. In other words, if the need arises for the type of seeds to be changed, or when a granular fertilizer must be dispensed instead of seeds, it is necessary for an entire set of specific rotators to be available, which must then be duly mounted in the dispenser under a considerable waste of time and a lot of physical effort.
Nor should the problem of the operating timeliness in the case of seeding be forgotten, either. Seeding is in fact a process that requires the utmost rapidity in adjusting the dispenser, considering the persisting need for due advantage to be taken each time from the most favourable weather conditions.
It therefore is a main purpose of the present invention to provide a dispenser of seeds, fertilizers and the like, which is really multi-functional thanks to its being adjustable in accordance with the various types and kinds of substances to be dispensed, without any need arising for the mechanical parts that make up the same dispenser to be replaced.
A further purpose of the present invention is to ensure a more accurate and even sorting of the products to be dispensed, through the use of a single, particularly shaped rotator provided with a cladding of soft material, which enables the products themselves to be stirred within the container and ejected onto the soil without giving rise to any cavitation effect in the mass of the same products due to the products being drawn in from below.
Yet, a further purpose of the present invention is to provide a dispenser that enables a plurality of furrows in the soil to be fed (i.e., sown) at the same time, so as to achieve a plurality of cultivated rows, with the aid of a control device that is simple and reliable.
The present invention also enables different doses of the same product or substance to be dispensed by adjusting the dispenser and, therefore, the interference between the rotator and the guiding disc, without having to act on the motor drive (i.e. by changing the speed stage of a transmission gear, adjusting the revolution speed of the motor or the like).